Reciprocating-rotary motion conversion device

ABSTRACT

A reciprocating-rotary motion conversion unit that is particularly adapted for use with a conventional cylinder, piston and wrist pin to more efficiently utilize the power generated when charges of fuel are intermittently exploded in timed sequence within the cylinder. The increased efficiency is attained by a unique connecting rod and gear assembly that are so operatively associated with the wrist pin and a drive shaft that the latter is rotated more than one revolution for each reciprocating cycle of the piston. In addition, the gear assembly is of such design that it has a throw that is twice the stroke of the piston, and as a result the torque exerted on the drive shaft is increased. The invention is highly advantageous from an ecology standpoint in an automotive application as a simple reciprocating cycle of the piston results in the drive shaft being rotated more than one revolution rather than one revolution as occurs in a conventional internal combustion engine. Also, due to the increased number of revolutions of the drive shaft for each cycle of reciprocation of the piston, less fuel is burned by a vehicle over that consumed in a conventional internal combustion engine, in rotating the drive shaft the same number of revolutions, and accordingly less products of combustion are discharged to the ambient atmosphere. The present invention while most adaptable to automotive combustion engines may also be used advantageously for a high speed motor to rotate the drive shaft and impart relatively low speed reciprocating movement to a piston, such as is required in pumps and the like.

United States Patent Wieckmann 51 Sept. 26, 1972 [54]RECIPROCATING-ROTARY MOTION CONVERSION DEVICE [72] Inventor: GerhardWieckmann, 20311 Gresham St., Canoga Park, Calif. 91306 [22] Filed: July8,1971

[21] App1.No.: 160,663

[52] U.S.Cl. ..74/52,123/l97 AC [51] Int.Cl. ..Fl6h 37/12 [58] Field ofSearch ..74/52; 123/197 AC, 197 R [56] References Cited UNITED STATESPATENTS 1,191,827 7/1916 Reese ..123/197 AC 1,326,129 12/1919 Chadbourne..74/52 1,863,667 6/1932 Miranda ..74/52 1,977,075 10/1934 Magnuson....;..123/197R 2,199,625 5/1940 Fern-brugg ..74/52 Primary Examiner-WilliamF. ODea Assistant Examiner-Wesley S. Ratliff, .lr. Attorney-William C.Babcock 5 7 ABSTRACT A reciprocating-rotary motionconversion unit thatis particularly adapted for use with a conventional cylinder, piston andwrist pin to more efficiently utilize the power generated when chargesof fuel are intermittently exploded in timed sequence within thecylinder.

' assembly is of such design that it has a throw that is twice thestroke of the piston, and as a result the torque exerted on the driveshaft is increased.

The invention is highly advantageous from an ecology standpoint in anautomotive application as a simple reciprocating cycle of the pistonresults in the drive shaft being rotated more than one revolution ratherthan one revolution as occurs in a conventional internal combustionengine. Also, due to the increased number of revolutions of the driveshaft for each cycle of reciprocation of the piston, less fuel is burnedby a vehicle over that consumed in a conventional internal combustionengine, in rotating the drive shaft the same number of revolutions, andaccordingly less products of combustion are discharged to the ambientatmosphere.

The present invention while most adaptable to automotive combustionengines may also be used advantageously for a high speed motor to rotatethe drive shaft and impart relatively low speed reciprocating movementto a piston, such as is required in pumps and the like.

6 Claims, 7 Drawing Figures PATENTEDSEP26 m2 SHEET 2 [IF 3 W rk I yjiw g4 RECIPROCA'IING-ROTARY MOTION CONVERSION DEVICE BACKGROUND OF THEINVENTION 1. Field of the Invention A reciprocating-rotary motionconversion device.

Description of the Prior Art 2. In the conventional internal combustionengine each full reciprocating cycle of a piston results in a crankshaftoperatively associated therewith rotating but one revolution. Also inthe conventional reciprocating invention the stroke of the piston is thesame as the throw of the crankshaft. As a result, unless the stroke ofthe piston is relatively great, the force exerted by the piston on themoment arm of the crankshaft at the time of the initial explosion of thefuel charge is relatively small, and maximum torque on the crankshaft isnot attained.

In the present invention the operational disadvantages of the prior artinternal combustion engines in this regard is overcome, in that thethrow of the connecting rod gear assembly is twice the stroke of thepiston, and as a result maximum torque is attained from the explodingcharges. In addition, each reciprocating cycle of the piston when thepresent invention is employed results in the drive shaft being rotated anumber of revolutions, rather than one revolution as occurs in aconventional engine.

The present invention provides the further operational advantage when itis used in an automotive vehicle, that greater mileage is attained fromthe vehicle, and as a result contamination of the ambient atmospherefrom products of combustion is lowered due to the use of less fuel permile.

The present invention also provides the operational advantage that ahigh speed motor can be used in conjunction therewith, with theinvention converting high speed rotary motion to relatively low speedreciprocating motion on a piston or the like.

SUMMARY OF THE INVENTION A reciprocating rotary motion conversion deviceparticularly adapted for use with the cylinder and piston having timedignition means associated therewith, to obtain increased torque on thedrive shaft, as well as additional rotational movement of the driveshaft for each reciprocating cycle of the piston. The connectingrod-gear assembly is pivotally connected to the wrist pin of the pistonin such a manner, that the throw of the assembly is twice or more thestroke of the piston. This arrangement permits the force of theexploding charge in the cylinder to be transferred to the drive shaft toincrease the torque thereon, and obtain maximum power from the fuel, aswell as increased efficiency in the operating characteristics of theengine.

A major object of the present invention is to provide areciprocating-rotary motion conversion device for use with a piston insuch a manner that the throw on the crankshaft is twice or more thestroke of the piston, and as a result improving the torquecharacteristics of an engine with which it is associated, as well ascausing the drive shaft to rotate a number of revolutions for eachreciprocating cycle of the piston rather than the single revolutionattained in a conventional internal combustion engine.

Another object of the invention is to permit either reciprocating motionto be transformed to rotary motion or rotary motion to reciprocatingmotion by a relatively simply mechanical device, and one that permitsthese conversions to be carried out with a high degree of efficiency,and within a relatively small space.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a transverse cross sectional viewof an internal combustion engine embodying the invention, and with thepiston disposed at substantially the top of its stroke;

FIG. 2 is the same transverse cross sectional view as shown in FIG. 1,but with the piston being at substantially the lowermost position of itsstroke;

FIG. 3 is a cross sectional view of a first form of the invention takenon the line 3-3 of FIG. 1;

FIG. 4 is a cross sectional view of a second form of the invention;

FIG. 5 is a transverse cross sectional view of a third form of theinvention;

FIG. .6 is a cross sectional view of the third form of the device takenon the line 6-6 of FIG. 5; and

FIG. 7 is a cross sectional view of the third form of the device takenon the line 77 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS and 3 that is operativelyassociated with a conventional cylinder defining member B that has aconventional piston C slidably mounted within the confines thereof.

The upper end of the cylinder defining member B is closed by aconventional head D that serves to removably support a spark plug E orother suitable ignition means, as well as a fuel inlet valve F anddischarge valve G.

The cylinder defining member B terminates on the lower end thereof inflanges 10 that are secured by bolts 12 or other suitable fasteningmeans to a crankcase H. The flanges 12 are in abutting contact with sidepieces 14 and 16 that partially define the crankcase H, with the firstside piece 14 having an end piece 18 extending therefrom that interlockswith a ribbed portion 20 of the second side piece 16 and is removablysecured thereto by bolts 22 or other suitable fastening means.

The first side piece 14 has an opening 14a formed therein that isengaged by a cylindrical boss 24 that forms a part of a hollow rigidbody 26. The interior surface of the boss 24 rigidly supports the outerrace 28 of a ball bearing assembly J. The assembly J includes an innerrace 30, and a sequence of balls 32 situated between the inner and outerraces.

Second; side wall 16 includes an outwardly cupshaped portion 34 that hasa bore 34a formed therein that is axially aligned with a counterbore 34balso defined in the portion 34. The bore 340 and counterbore 34b are attheir junction separated by an inwardly extending circular rib 34c. Thebore 34a serves to support a ball bearing assembly K that includes anouter race 36 and inner race 38 and a sequence of balls 40 situatedtherebetween. The counterbore 34b supports a ball bearing assembly Lthat has an outer race 42 that is seated in abutting contact with thebore 34a. Assembly L includes an inner race 44 and a sequence of balls46 situated between the two races 42 and 44.

The piston C is provided with a wrist pin 48 as is conventional withsuch devices, with the pin being pivotally connected to a connecting rodM that develops on its lower end into a relatively large ringshapedportion 50 that rigidly supports an internal gear 52 within the confinesthereof.

Two generally semi-circular first and second counterweights 54 and 56are provided that have gear carrier portions 54a and 56a extendingoutwardly therefrom and normally disposed thereto as best seen inFIG. 1. Counterweight 54a has a shaft 58 formed integral therewith asshown in FIG. 3 that extends outwardly therefrom. Shaft 58 is inengagement with the inner race 30 of ball bearing assembly J. The shaft58 has a gear 60 rigidly secured thereto, that is in toothed engagementwith a gear assembly 62 of conventional design, which gear assembly asit rotates is adapted to cause the sequential firing of the spark plugE, as well as causing the sequential opening of the valves F and G as isconventional with an internal combustion engine.

The counterweight portion 56a as shown in FIG. 3 has a number of bores56b formed therein that are axially aligned with tapped bores 54b formedin the counterweight portion 54a. Screws 64 extend through the bores 56band rigid tubular spacers 66 to engage the tapped bores 54b. The screws64 when tightened force the counterweight portions 54a and 560 intopressure abutting contact with the ends of the spacers 66 to provide aspace 68 of predetermined width between the counterweights 54 and 56 aswell as the portions 54a and 56a.

Three equally spaced openings 56c are formed in the counterweightportion 56a and are axially aligned with tapped bores 54c formed in thecounterweight portion 55a. The three openings 56c have screws 68extending therethrough that rotatably support planetary gears 70a, 70band 70c when the threaded portion of the screws are in engagement withthe tapped bores 54c. The gears 70a, 70b and 700 as may best be seen inFIG. 1 are in toothed engagement with the internal gear 52.

Counterweight 56 as shown in FIG. 3 has a hollow tubular shaft 72extending outwardly therefrom that has the exterior surface thereof inabutting contact with the interior surface of the inner race 36 andbeing rotatably supported relative to the crankcase H as a resultthereof. The shaft 72 has a longitudinally extending bore 74 formedtherein with the bore 74 on its inner end supporting a conventional ballbearing assembly 76. A recess 78 formed in the first counterweight 54also serves to support a ball bearing assembly 80 that is identical tothe ball bearing assembly 76.

The inner race 44 of ball bearing assembly L rotatably supports a driveshaft N that develops on its left hand end into a section 82 of smallerdiameter, and this section in turn on its left hand end developing intoa second section 84 of still smaller diameter. The second section 84 isby a key 86 rigidly secured to a drive gear 88, which drive gear is intoothed engagement with the internal gear 52. The second drive shaftsection 84 as can best be seen in FIG. 3 is rotatably supported by theinner races of the ball bearing assemblies 76 and 78.

When the piston C is at the top of the stroke as shown in FIG. 1, thegear a is vertically and axially aligned with the center of the drivegear 88. The distance 8 between the center of the gear 70a and the gear88 determines the stroke of the piston C. In FIG. 1 it will be seen thatthe center of the gear 70a is a distance S above the center of the gear88. The gear 88 rotates in a stationary position relative to thecrankcase H as shown in FIG. 3.

When the piston C has moved downwardly to the bottom of the stroke asshown in FIG. 2, the gear 70a is now axially and vertically aligned withthe gear 88, but is situated the distance S therebelow. Thus, the throwof the counterweight carrier portions 54a and 560 with the gearsoperatively associated therewith is 2S, which is twice the stroke of thepiston C, in contrast to the stroke and throw being the same as occursin a conventional internal combustion engine in which a conventionalpiston, connecting rod and crankshaft are used.

The distance S provides an increased lever arm for the force exerted bythe exploding charge of fuel (not shown) in the cylinder B to act on,and accordingly the energy of the exploding charge exerts a greatertorque on the drive shaft N as well as rotating the drive shaft morethan one revolution for each complete reciprocating cycle of the pistonC. The number of revolutions that the drive shaft N will rotate for eachcomplete reciprocating cycle of the piston C is determined by:

(pitch diameter internal gear 52)/( pitch diameter drive gear-88) lnumber of rotations of drive shaft N for each complete reciprocatingcycle of piston C A second form of the invention A is shown in FIG. 4that is identical with the first form, other than that the drive shaft Nmerely has one section 82' extending therefrom which by a key 90 issecured to the shaft 58'. The shaft 58' is not connected to thecounterweight 54' as in the first form of the invention, and as a resultthe shaft N and shaft 58' rotate at the same speed and in the samedirection. The shaft 58 in the first form of the invention rotates onerevolution for each complete reciprocating cycle of the piston C. Thecup-shaped portion 34 is eliminated in the second side piece 16 in thesecond form of the invention A and the shaft N A being rotatablysupported by two ball bearing assemblies K and L' that are of the samesize and removably held in a fixed position relative to the second sidepiece 16' by a removably ring-shaped plate 92 that is secured thereto byscrews 94 or other suitable fastening means. Elements in the second formA of the invention that are common to the first form A are designated onthe drawings by the same numbers and letters but with a prime beingadded thereto.

A third form A" of the invention is shown in FIGS. 5, 6, and 7 that issimilar in structure to the first form A.

Elements of the third form A" that are common to the first form A aredesignated on the drawing by the same numbers and letters as used in thefirst form but with double primes being added thereto.

The third form A" differs primarily from the first form A in that thedrive gear 88" is not in toothed engagement with the internal gear 52"as is clearly shown in FIG. 5, and with the drive gear being secured byconventional means 96. A drive gear 88 is in toothed engagement withplanetary gear 70a" and this latter gear also being in engagement withthe internal gear 52 The planetary gear 700" is illustrated in FIG. 5 asbeing of substantially larger diameter than the planetary gears 70b" and70c". The counterweight gear carrier portions 54a" and 56a" haverecesses formed therein in 1 which identical ball bearing assemblies Uand V are disposed that rotatably engage the shaft Q.

The distance S" between the center of rotation of the planetary gear70a" and the center of the gear 88" determines the throw of the pistonC". The throw of the carrier portions 54a" and 56a" with the associatedgears is 28'. The number of rotations that the shaft Q will make foreach complete reciprocating cycle of the piston C" is determined by thefollowings:

(Pitch diameter internal gear 52b")! (Pitch diameter drive gear 88")+ 1=Number of rotations of drive shaft 0 for each complete reciprocatingcycle of piston C" The use and operation of the three forms of theinvention have previously been described in detail and furtherdescription is accordingly not required.

The invention has been illustrated as being applied to an internalcombustion engine, but it will be obvious that if a motor (not shown) iscaused to drive the shaft N, N or Q, and appropriate fluid inlet andoutlets are provided in conjunction with the cylinder defining member B,B or B", that a high speed motor may be used to impart relatively slowreciprocating movement to the piston for pumping purposes or the like.

Iclaim:

1. In combination with a cylinder defining member, a piston slidablysupported in said cylinder, said piston including a wrist pin, a hollowcase connected to said cylinder defining member, said case includingfirst and second side pieces, a first drive shaft rotatably sup portedin said case, a device for selectively transforming reciprocatingmovement of said piston to rotary motion of said piston to rotary motionof said drive shaft or rotary motion of said drive shaft toreciprocating movement of said piston, said device including:

a. a connecting rod that has first and second end portions, said firstend pivotally connected to said wrist pin, said end portion disposed insaid case, second end said second end portion in the form of a ring thathas an internal diameter substantially greater than the diameter of saiddrive shaft, and said shaft extending through said second end portion;

b. an internal gear rigidly secured to the interior of said second endportion;

0. a drive gear rigidly secured to said drive shaft, said drive gearsituated in said case and within the confines of said internal gear andin toothed engagement with the latter;

d. two laterally spaced first and second counterweights that includeoutwardly extending first and second gear carrier portions that aredisposed in said case on opposite sides of said second portion of saidconnecting rod;

e. first means that rotatably support said first and secondcounterweights and carrier portions in said case to revolve about thelongitudinal axis of said drive shaft;

f. second means for holding said first and second counterweights andcarrier portions in predetermined lateral spacing; and

g. at least one planetary gear rotatably supported between said firstand second gear carrier portions and in toothed engagement with saidinternal gear, with the centers of rotation of said drive gear andplanetary gear being coaxially aligned on the Ion gitudinal axis of saidconnecting rod when said piston is a maximum distance from said driveshaft, with the distance between the centers of rotation of said drivegear and planetary gear being the stroke of said piston as said driveshaft rotates, with the throw of said planetary gear being twice saidstroke as said counterweights and gear carrier portions rotate about thecenter of rotation of said drive gear, and the number of rotations saiddrive shaft makes for each complete reciprocating cycle of said pistonbeing the ratio of the internal tooth diameter of said internal gear tothe tooth diameter of said drive gear minus one.

2. A device as defined in claim 1 in which said drive shaft is joumalledin a portion of said second side piece, and said first means includes:

h. a first shaft that extends outwardly from said first counterweightand a second tubular shaft that extends outwardly from said secondcounterweight away from said first shaft and that envelopes at least apart of said drive shaft; and

i. first and second bearings rigidly supported from said first andsecond side pieces that rotatably support said first and second shafts,with said first shaft rotating at a different rate of rotation than saiddrive shaft.

3. A device as defined in claim 1 in which said first means includes:

h. a first shaft coaxially aligned with said drive shaft;

i. key means for removably connecting said first shaft to said driveshaft, with said drive shaft and first shaft having portions thereofextending through transversely aligned openings in said counterweight;and

j. first and second bearings supported from said first and second sidepieces, with said first and second bearings rotatably supporting saidfirst shaft and said drive shaft.

4. A device as defined in claim 1 in which said drive shaft extendsthrough transversely aligned openings in said first and secondcounterweights, and said first means are first and second bearingsmounted on said first and second side pieces and rotatably supportingsaid drive shaft.

5. In combination with a cylinder defining member, a piston slidablysupported in said cylinder, said piston including a wrist pin, a hollowcase connected to said cylinder defining member, said case includingfirst and second side pieces, a first drive shaft rotatably supported insaid case, a device for selectively transforming reciprocating movementof said piston to rotary motion of said piston to rotary motion of saiddrive shaft or rotary motion of said drive shaft to reciprocatingmovement of said piston, said device including:

a. a connecting rod that has first and second end portions, said firstend pivotally connected to said writs pin, said second end portiondisposed in said case, with said second end portion in the form of aring that has an internal diameter substantially greater than thediameter of said drive shaft, and said shaft extending through saidsecond end portion;

b. an internal gear rigidly secured to the interior of said second endportion;

c. a drive gear rigidly secured to said drive shaft said drive gearsituated in said case and within the confines of said internal gear, butnot in toothed engagement with the latter;

d. two laterally spaced first and second counterweights that includeoutwardly extending first and second gear carrier portions that aredisposed in said case on opposite sides of said second portion of saidconnection rod;

e. first means that rotatably support said first and secondcounterweights and carrier portions in said case to revolve about thelongitudinal axis of said drive shaft;

f. second means for holding said first and second counterweights andcarrier portions in predetermined lateral spacing; and

g. at least one planetary gear rotatably supported between said firstand second gear carrier portions and in toothed engagement with saidinternal gear and said drive gear, with the centers of rotation of saiddrive gear and planetary gear being coaxially aligned on thelongitudinal axis of said connecting rod when said piston is a maximumdistance from said drive shaft, with the distance between the centers ofrotation of said drive gear and planetary gear being the length of thestroke of said piston as said drive shaft rotates, with the throw ofsaid planetary gear being twice said stroke as said counterweights andgear carrier portions rotate about the center of rotation of said drivegear, and the number of rotations said drive shaft makes for eachcomplete reciprocating cycle of said piston being the ratio of theinternal tooth diameter of said internal gear to the tooth diameter ofsaid drive gear plus one.

6. A device as defined in claim 5 in which said drive gear extendsthrough transversely aligned openings formed in said counterweights, andsaid first means are bearings mounted in said openings that rotatablysupport said drive shaft.

1. In combination with a cylinder defining member, a piston slidablysupported in said cylinder, said piston including a wrist pin, a hollowcase connected to said cylinder defining member, said case includingfirst and second side pieces, a first drive shaft rotatably supported insaid case, a device for selectively transforming reciprocating movementof said piston to rotary motion of said piston to rotary motion of saiddrive shaft or rotary motion of said drive shaft to reciprocatingmovement of said piston, said device including: a. a connecting rod thathas first and second end portions, said first end pivotally connected tosaid wrist pin, said end portion disposed in said case, second end saidsecond end portion in the form of a ring that has an internal diametersubstantially greater than the diameter of said drive shaft, and saidshaft extending through said second end portion; b. an internal gearrigidly secured to the interior of said second end portion; c. a drivegear rigidly secured to said drive shaft, said drive gear situated insaid case and within the confines of said internal gear and in toothedengagement with the latter; d. two laterally spaced first and secondcounterweights that include outwardly extending first and second gearcarrier portions that are disposed in said case on opposite sides ofsaid second portion of said connecting rod; e. first means thatrotatably support said first and second counterweights and carrierportions in said case to revolve about the longitudinal axis of saiddrive shaft; f. second means for holding said first and secondcounterweights and carrier portions in predetermined lateral spacing;and g. at least one planetary gear rotatably supported between saidfirst and second gear carrier portions and in toothed engagement withsaid internal gear, with the centers of rotation of said drive gear andplanetary gear being coaxially aligned on the longitudinal axis of saidconnecting rod when said piston is a maximum distance from said driveshaft, with the distance between the centers of rotation of said drivegear and planetary gear being the stroke of said piston as said driveshaft rotates, with the throw of said planetary gear being twice saidstroke as said counterweights and gear carrier portions rotate about thecenter of rotation of said drive gear, and the number of rotations saiddrive shaft makes for each complete reciprocating cycle of said pistonbeing the ratio of the internal tooth diameter of said internal gear tothe tooth diameter of said drive gear minus one.
 2. A device as definedin claim 1 in which said drive shaft is journalled in a portion of saidsecond side piece, and said first means includes: h. a first shaft thatextends outwardly from said first counterweight and a second tubularshaft that extends outwardly from said second counterweight away fromsaid first shaft and that envelopes at least a part of said drive shaft;and i. first and second bearings rigidly supported from said first andsecond side pieces that rotatably support said first and second shafts,with said first shaft rotating at a different rate of rotation than saiddrive shaft.
 3. A device as defined in claim 1 in which said first meansincludes: h. a first shaft coaxially aligned with said drive shaft; i.key means for removably connecting said first shaft to said drive shaft,with said drive shaft and first shaft having portions thereof extendingthrough transversely aligned openings in said counterweight; and j.first and second bearings supported from said first and second sidepieces, with said first and second bearings rotatably supporting saidfirst shaft and said drive shaft.
 4. A device as defined in claim 1 inwhich said drive shaft extends through transversely aligned openings insaid first and second counterweights, and said first means are first andsecond bearings mounted on said first and second side pieces androtatably supporting said drive shaft.
 5. In combination with a cylinderdefining member, a piston slidably supported in said cylinder, saidpiston including a wrist pin, a hollow case connected to said cylinderdefining member, said case including first and second side pieces, afirst drive shaft rotatably supported in said case, a device forselectively transforming reciprocating movement of said piston to rotarymotion of said piston to rotary motion of said drive shaft or rotarymotion of said drive shaft to reciprocating movement of said piston,said device including: a. a connecting rod that has first and second endportions, said first end pivotally connected to said writs pin, saidsecond end portion disposed in said case, with said second end portionin the form of a ring that has an internal diameter substantiallygreater than the diameter of said drive shaft, and said shaft extendingthrough said second end portion; b. an internal gear rigidly secured tothe interior of said second end portion; c. a drive gear rigidly securedto said drive shaft said drive gear situated in said case and within theconfines of said internal gear, but not in toothed engagement with thelatter; d. two laterally spaced first and second counterweights thatinclude outwardly extending first and second gear carrier portions thatare disposed in said case on opposite sides of said second portion ofsaid connection rod; e. first means that rotatably support said firstand second counterweights and carrier portions in said case to revolveabout the longitudinal axis of said drive shaft; f. second means forholding said first and second counterweights and carrier portions inpredetermined lateral spacing; and g. at least one planetary gearrotatably supported between said first and second gear carrier portionsand in toothed engagement with said internal gear and said drive gear,with the centers of rotation of said drive gear and planetary gear beingcoaxially aligned on the longitudinal axis of said connecting rod whensaid piston is a maximum distance from said drive shaft, with thedistance between the centers of rotation of said drive gear andplanetary gear being the length of the stroke of said piston as saiddrive shaft rotates, with the throw of said planetary gear being twicesaid stroke as said counterweights and gear carrier portions rotateabout the center of rotation of said drive gear, and the number ofrotations said drive shaft makes for each complete reciprocating cycleof said piston being the ratio of the internal tooth diameter of saidinternal gear to the tooth diameter of said drive gear plus one.
 6. Adevice as defined in claim 5 in which said drive gear extends throughtransversely aligned openings formed in said counterweights, and saidfirst means are bearings mounted in said openings that rotatably supportsaid drive shaft.